/*
 * Copyright 2007 ZXing authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/*namespace com.google.zxing.qrcode.detector {*/

    import DecodeHintType from '../../DecodeHintType';
    import ResultPoint from '../../ResultPoint';
    import ResultPointCallback from '../../ResultPointCallback';
    import BitMatrix from '../../common/BitMatrix';
    import FinderPattern from './FinderPattern';
    import FinderPatternInfo from './FinderPatternInfo';
    
    import NotFoundException from '../../NotFoundException';
    
    /*import java.io.Serializable;*/
    /*import java.util.ArrayList;*/
    /*import java.util.Collections;*/
    /*import java.util.Comparator;*/
    /*import java.util.List;*/
    /*import java.util.Map;*/
    
    /**
     * <p>This class attempts to find finder patterns in a QR Code. Finder patterns are the square
     * markers at three corners of a QR Code.</p>
     *
     * <p>This class is thread-safe but not reentrant. Each thread must allocate its own object.
     *
     * @author Sean Owen
     */
    export default class FinderPatternFinder {
    
        private static CENTER_QUORUM = 2;
        protected static MIN_SKIP = 3; // 1 pixel/module times 3 modules/center
        protected static MAX_MODULES = 57; // support up to version 10 for mobile clients
    
        private possibleCenters: FinderPattern[];
        private hasSkipped: boolean;
        private crossCheckStateCount: Int32Array;
    
        /**
         * <p>Creates a finder that will search the image for three finder patterns.</p>
         *
         * @param image image to search
         */
        // public constructor(image: BitMatrix) {
        //   this(image, null)
        // }
    
        public constructor(private image: BitMatrix, private resultPointCallback: ResultPointCallback) {
            this.possibleCenters = [];
            this.crossCheckStateCount = new Int32Array(5);
            this.resultPointCallback = resultPointCallback;
        }
    
        protected getImage(): BitMatrix {
            return this.image;
        }
    
        protected getPossibleCenters(): FinderPattern[] {
            return this.possibleCenters;
        }
    
        public find(hints: Map<DecodeHintType, any>): Array<FinderPatternInfo> /*throws NotFoundException */ {
            const tryHarder: boolean = (hints !== null && hints !== undefined) && undefined !== hints.get(DecodeHintType.TRY_HARDER);
            const pureBarcode: boolean = (hints !== null && hints !== undefined) && undefined !== hints.get(DecodeHintType.PURE_BARCODE);
            const image = this.image;
            const maxI = image.getHeight();
            const maxJ = image.getWidth();
            // We are looking for black/white/black/white/black modules in
            // 1:1:3:1:1 ratio; this tracks the number of such modules seen so far
    
            // Let's assume that the maximum version QR Code we support takes up 1/4 the height of the
            // image, and then account for the center being 3 modules in size. This gives the smallest
            // number of pixels the center could be, so skip this often. When trying harder, look for all
            // QR versions regardless of how dense they are.
            let iSkip = Math.floor((3 * maxI) / (4 * FinderPatternFinder.MAX_MODULES));
            if (iSkip < FinderPatternFinder.MIN_SKIP || tryHarder) {
                iSkip = FinderPatternFinder.MIN_SKIP;
            }
    
            let done: boolean = false;
            const stateCount = new Int32Array(5);
            for (let i = iSkip - 1; i < maxI && !done; i += iSkip) {
                // Get a row of black/white values
                stateCount[0] = 0;
                stateCount[1] = 0;
                stateCount[2] = 0;
                stateCount[3] = 0;
                stateCount[4] = 0;
                let currentState = 0;
                for (let j = 0; j < maxJ; j++) {
                    if (image.get(j, i)) {
                        // Black pixel
                        if ((currentState & 1) === 1) { // Counting white pixels
                            currentState++;
                        }
                        stateCount[currentState]++;
                    } else { // White pixel
                        if ((currentState & 1) === 0) { // Counting black pixels
                            if (currentState === 4) { // A winner?
                                if (FinderPatternFinder.foundPatternCross(stateCount)) { // Yes
                                    const confirmed: boolean = this.handlePossibleCenter(stateCount, i, j, pureBarcode);
                                    if (confirmed === true) {
                                        // Start examining every other line. Checking each line turned out to be too
                                        // expensive and didn't improve performance.
                                        iSkip = 2;
                                        if (this.hasSkipped === true) {
                                            done = this.haveMultiplyConfirmedCenters();
                                        } else {
                                            const rowSkip = this.findRowSkip();
                                            if (rowSkip > stateCount[2]) {
                                                // Skip rows between row of lower confirmed center
                                                // and top of presumed third confirmed center
                                                // but back up a bit to get a full chance of detecting
                                                // it, entire width of center of finder pattern
    
                                                // Skip by rowSkip, but back off by stateCount[2] (size of last center
                                                // of pattern we saw) to be conservative, and also back off by iSkip which
                                                // is about to be re-added
                                                i += rowSkip - stateCount[2] - iSkip;
                                                j = maxJ - 1;
                                            }
                                        }
                                    } else {
                                        stateCount[0] = stateCount[2];
                                        stateCount[1] = stateCount[3];
                                        stateCount[2] = stateCount[4];
                                        stateCount[3] = 1;
                                        stateCount[4] = 0;
                                        currentState = 3;
                                        continue;
                                    }
                                    // Clear state to start looking again
                                    currentState = 0;
                                    stateCount[0] = 0;
                                    stateCount[1] = 0;
                                    stateCount[2] = 0;
                                    stateCount[3] = 0;
                                    stateCount[4] = 0;
                                } else { // No, shift counts back by two
                                    stateCount[0] = stateCount[2];
                                    stateCount[1] = stateCount[3];
                                    stateCount[2] = stateCount[4];
                                    stateCount[3] = 1;
                                    stateCount[4] = 0;
                                    currentState = 3;
                                }
                            } else {
                                stateCount[++currentState]++;
                            }
                        } else { // Counting white pixels
                            stateCount[currentState]++;
                        }
                    }
                }
                if (FinderPatternFinder.foundPatternCross(stateCount)) {
                    const confirmed: boolean = this.handlePossibleCenter(stateCount, i, maxJ, pureBarcode);
                    if (confirmed === true) {
                        iSkip = stateCount[0];
                        if (this.hasSkipped) {
                            // Found a third one
                            done = this.haveMultiplyConfirmedCenters();
                        }
                    }
                }
            }
    
            const patternInfo: Array<Array<FinderPattern>> = this.selectBestPatterns();

            ResultPoint.orderBestMultiplePatterns(patternInfo);

            return patternInfo.map((item, index) => new FinderPatternInfo(patternInfo[index]));
        }
    
        /**
         * Given a count of black/white/black/white/black pixels just seen and an end position,
         * figures the location of the center of this run.
         */
        private static centerFromEnd(stateCount: Int32Array, end: number /*int*/): number/*float*/ {
            return (end - stateCount[4] - stateCount[3]) - stateCount[2] / 2.0;
        }
    
        /**
         * @param stateCount count of black/white/black/white/black pixels just read
         * @return true iff the proportions of the counts is close enough to the 1/1/3/1/1 ratios
         *         used by finder patterns to be considered a match
         */
        protected static foundPatternCross(stateCount: Int32Array): boolean {
            let totalModuleSize = 0;
            for (let i = 0; i < 5; i++) {
                const count = stateCount[i];
                if (count === 0) {
                    return false;
                }
                totalModuleSize += count;
            }
            if (totalModuleSize < 7) {
                return false;
            }
            const moduleSize: number /*float*/ = totalModuleSize / 7.0;
            const maxVariance: number /*float*/ = moduleSize / 2.0;
            // Allow less than 50% variance from 1-1-3-1-1 proportions
            return Math.abs(moduleSize - stateCount[0]) < maxVariance &&
                Math.abs(moduleSize - stateCount[1]) < maxVariance &&
                Math.abs(3.0 * moduleSize - stateCount[2]) < 3 * maxVariance &&
                Math.abs(moduleSize - stateCount[3]) < maxVariance &&
                Math.abs(moduleSize - stateCount[4]) < maxVariance;
        }
    
        private getCrossCheckStateCount(): Int32Array {
            const crossCheckStateCount = this.crossCheckStateCount;
            crossCheckStateCount[0] = 0;
            crossCheckStateCount[1] = 0;
            crossCheckStateCount[2] = 0;
            crossCheckStateCount[3] = 0;
            crossCheckStateCount[4] = 0;
            return crossCheckStateCount;
        }
    
        /**
         * After a vertical and horizontal scan finds a potential finder pattern, this method
         * "cross-cross-cross-checks" by scanning down diagonally through the center of the possible
         * finder pattern to see if the same proportion is detected.
         *
         * @param startI row where a finder pattern was detected
         * @param centerJ center of the section that appears to cross a finder pattern
         * @param maxCount maximum reasonable number of modules that should be
         *  observed in any reading state, based on the results of the horizontal scan
         * @param originalStateCountTotal The original state count total.
         * @return true if proportions are withing expected limits
         */
        private crossCheckDiagonal(startI: number /*int*/, centerJ: number /*int*/, maxCount: number /*int*/, originalStateCountTotal: number /*int*/): boolean {
            const stateCount: Int32Array = this.getCrossCheckStateCount();
    
            // Start counting up, left from center finding black center mass
            let i = 0;
            const image = this.image;
            while (startI >= i && centerJ >= i && image.get(centerJ - i, startI - i)) {
                stateCount[2]++;
                i++;
            }
    
            if (startI < i || centerJ < i) {
                return false;
            }
    
            // Continue up, left finding white space
            while (startI >= i && centerJ >= i && !image.get(centerJ - i, startI - i) &&
                stateCount[1] <= maxCount) {
                stateCount[1]++;
                i++;
            }
    
            // If already too many modules in this state or ran off the edge:
            if (startI < i || centerJ < i || stateCount[1] > maxCount) {
                return false;
            }
    
            // Continue up, left finding black border
            while (startI >= i && centerJ >= i && image.get(centerJ - i, startI - i) &&
                stateCount[0] <= maxCount) {
                stateCount[0]++;
                i++;
            }
            if (stateCount[0] > maxCount) {
                return false;
            }
    
            const maxI = image.getHeight();
            const maxJ = image.getWidth();
    
            // Now also count down, right from center
            i = 1;
            while (startI + i < maxI && centerJ + i < maxJ && image.get(centerJ + i, startI + i)) {
                stateCount[2]++;
                i++;
            }
    
            // Ran off the edge?
            if (startI + i >= maxI || centerJ + i >= maxJ) {
                return false;
            }
    
            while (startI + i < maxI && centerJ + i < maxJ && !image.get(centerJ + i, startI + i) &&
                stateCount[3] < maxCount) {
                stateCount[3]++;
                i++;
            }
    
            if (startI + i >= maxI || centerJ + i >= maxJ || stateCount[3] >= maxCount) {
                return false;
            }
    
            while (startI + i < maxI && centerJ + i < maxJ && image.get(centerJ + i, startI + i) &&
                stateCount[4] < maxCount) {
                stateCount[4]++;
                i++;
            }
    
            if (stateCount[4] >= maxCount) {
                return false;
            }
    
            // If we found a finder-pattern-like section, but its size is more than 100% different than
            // the original, assume it's a false positive
            const stateCountTotal = stateCount[0] + stateCount[1] + stateCount[2] + stateCount[3] + stateCount[4];
            return Math.abs(stateCountTotal - originalStateCountTotal) < 2 * originalStateCountTotal &&
                FinderPatternFinder.foundPatternCross(stateCount);
        }
    
        /**
         * <p>After a horizontal scan finds a potential finder pattern, this method
         * "cross-checks" by scanning down vertically through the center of the possible
         * finder pattern to see if the same proportion is detected.</p>
         *
         * @param startI row where a finder pattern was detected
         * @param centerJ center of the section that appears to cross a finder pattern
         * @param maxCount maximum reasonable number of modules that should be
         * observed in any reading state, based on the results of the horizontal scan
         * @return vertical center of finder pattern, or {@link Float#NaN} if not found
         */
        private crossCheckVertical(startI: number /*int*/, centerJ: number /*int*/, maxCount: number /*int*/,
            originalStateCountTotal: number /*int*/): number/*float*/ {
            const image: BitMatrix = this.image;
    
            const maxI = image.getHeight();
            const stateCount: Int32Array = this.getCrossCheckStateCount();
    
            // Start counting up from center
            let i = startI;
            while (i >= 0 && image.get(centerJ, i)) {
                stateCount[2]++;
                i--;
            }
            if (i < 0) {
                return NaN;
            }
            while (i >= 0 && !image.get(centerJ, i) && stateCount[1] <= maxCount) {
                stateCount[1]++;
                i--;
            }
            // If already too many modules in this state or ran off the edge:
            if (i < 0 || stateCount[1] > maxCount) {
                return NaN;
            }
            while (i >= 0 && image.get(centerJ, i) && stateCount[0] <= maxCount) {
                stateCount[0]++;
                i--;
            }
            if (stateCount[0] > maxCount) {
                return NaN;
            }
    
            // Now also count down from center
            i = startI + 1;
            while (i < maxI && image.get(centerJ, i)) {
                stateCount[2]++;
                i++;
            }
            if (i === maxI) {
                return NaN;
            }
            while (i < maxI && !image.get(centerJ, i) && stateCount[3] < maxCount) {
                stateCount[3]++;
                i++;
            }
            if (i === maxI || stateCount[3] >= maxCount) {
                return NaN;
            }
            while (i < maxI && image.get(centerJ, i) && stateCount[4] < maxCount) {
                stateCount[4]++;
                i++;
            }
            if (stateCount[4] >= maxCount) {
                return NaN;
            }
    
            // If we found a finder-pattern-like section, but its size is more than 40% different than
            // the original, assume it's a false positive
            const stateCountTotal = stateCount[0] + stateCount[1] + stateCount[2] + stateCount[3] +
                stateCount[4];
            if (5 * Math.abs(stateCountTotal - originalStateCountTotal) >= 2 * originalStateCountTotal) {
                return NaN;
            }
    
            return FinderPatternFinder.foundPatternCross(stateCount) ? FinderPatternFinder.centerFromEnd(stateCount, i) : NaN;
        }
    
        /**
         * <p>Like {@link #crossCheckVertical(int, int, int, int)}, and in fact is basically identical,
         * except it reads horizontally instead of vertically. This is used to cross-cross
         * check a vertical cross check and locate the real center of the alignment pattern.</p>
         */
        private crossCheckHorizontal(startJ: number /*int*/, centerI: number /*int*/, maxCount: number /*int*/,
            originalStateCountTotal: number /*int*/): number/*float*/ {
            const image: BitMatrix = this.image;
    
            const maxJ = image.getWidth();
            const stateCount: Int32Array = this.getCrossCheckStateCount();
    
            let j = startJ;
            while (j >= 0 && image.get(j, centerI)) {
                stateCount[2]++;
                j--;
            }
            if (j < 0) {
                return NaN;
            }
            while (j >= 0 && !image.get(j, centerI) && stateCount[1] <= maxCount) {
                stateCount[1]++;
                j--;
            }
            if (j < 0 || stateCount[1] > maxCount) {
                return NaN;
            }
            while (j >= 0 && image.get(j, centerI) && stateCount[0] <= maxCount) {
                stateCount[0]++;
                j--;
            }
            if (stateCount[0] > maxCount) {
                return NaN;
            }
    
            j = startJ + 1;
            while (j < maxJ && image.get(j, centerI)) {
                stateCount[2]++;
                j++;
            }
            if (j === maxJ) {
                return NaN;
            }
            while (j < maxJ && !image.get(j, centerI) && stateCount[3] < maxCount) {
                stateCount[3]++;
                j++;
            }
            if (j === maxJ || stateCount[3] >= maxCount) {
                return NaN;
            }
            while (j < maxJ && image.get(j, centerI) && stateCount[4] < maxCount) {
                stateCount[4]++;
                j++;
            }
            if (stateCount[4] >= maxCount) {
                return NaN;
            }
    
            // If we found a finder-pattern-like section, but its size is significantly different than
            // the original, assume it's a false positive
            const stateCountTotal = stateCount[0] + stateCount[1] + stateCount[2] + stateCount[3] +
                stateCount[4];
            if (5 * Math.abs(stateCountTotal - originalStateCountTotal) >= originalStateCountTotal) {
                return NaN;
            }
    
            return FinderPatternFinder.foundPatternCross(stateCount) ? FinderPatternFinder.centerFromEnd(stateCount, j) : NaN;
        }
    
        /**
         * <p>This is called when a horizontal scan finds a possible alignment pattern. It will
         * cross check with a vertical scan, and if successful, will, ah, cross-cross-check
         * with another horizontal scan. This is needed primarily to locate the real horizontal
         * center of the pattern in cases of extreme skew.
         * And then we cross-cross-cross check with another diagonal scan.</p>
         *
         * <p>If that succeeds the finder pattern location is added to a list that tracks
         * the number of times each location has been nearly-matched as a finder pattern.
         * Each additional find is more evidence that the location is in fact a finder
         * pattern center
         *
         * @param stateCount reading state module counts from horizontal scan
         * @param i row where finder pattern may be found
         * @param j end of possible finder pattern in row
         * @param pureBarcode true if in "pure barcode" mode
         * @return true if a finder pattern candidate was found this time
         */
        protected handlePossibleCenter(stateCount: Int32Array, i: number /*int*/, j: number /*int*/, pureBarcode: boolean): boolean {
            const stateCountTotal = stateCount[0] + stateCount[1] + stateCount[2] + stateCount[3] +
                stateCount[4];
            let centerJ: number /*float*/ = FinderPatternFinder.centerFromEnd(stateCount, j);
            let centerI: number /*float*/ = this.crossCheckVertical(i, /*(int) */Math.floor(centerJ), stateCount[2], stateCountTotal);
            if (!isNaN(centerI)) {
                // Re-cross check
                centerJ = this.crossCheckHorizontal(/*(int) */Math.floor(centerJ), /*(int) */Math.floor(centerI), stateCount[2], stateCountTotal);
                if (!isNaN(centerJ) &&
                    (!pureBarcode || this.crossCheckDiagonal(/*(int) */Math.floor(centerI), /*(int) */Math.floor(centerJ), stateCount[2], stateCountTotal))) {
                    const estimatedModuleSize: number /*float*/ = stateCountTotal / 7.0;
                    let found: boolean = false;
                    const possibleCenters = this.possibleCenters;
                    for (let index = 0, length = possibleCenters.length; index < length; index++) {
                        const center: FinderPattern = possibleCenters[index];
                        // Look for about the same center and module size:
                        if (center.aboutEquals(estimatedModuleSize, centerI, centerJ)) {
                            possibleCenters[index] = center.combineEstimate(centerI, centerJ, estimatedModuleSize);
                            found = true;
                            break;
                        }
                    }
                    if (!found) {
                        const point: FinderPattern = new FinderPattern(centerJ, centerI, estimatedModuleSize);
                        possibleCenters.push(point);
                        if (this.resultPointCallback !== null && this.resultPointCallback !== undefined) {
                            this.resultPointCallback.foundPossibleResultPoint(point);
                        }
                    }
                    return true;
                }
            }
            return false;
        }
    
        /**
         * @return number of rows we could safely skip during scanning, based on the first
         *         two finder patterns that have been located. In some cases their position will
         *         allow us to infer that the third pattern must lie below a certain point farther
         *         down in the image.
         */
        private findRowSkip(): number /*int*/ {
            const max = this.possibleCenters.length;
            if (max <= 1) {
                return 0;
            }
            let firstConfirmedCenter: ResultPoint = null;
            for (const center of this.possibleCenters) {
                if (center.getCount() >= FinderPatternFinder.CENTER_QUORUM) {
                    if (firstConfirmedCenter == null) {
                        firstConfirmedCenter = center;
                    } else {
                        // We have two confirmed centers
                        // How far down can we skip before resuming looking for the next
                        // pattern? In the worst case, only the difference between the
                        // difference in the x / y coordinates of the two centers.
                        // This is the case where you find top left last.
                        this.hasSkipped = true;
                        return /*(int) */Math.floor((Math.abs(firstConfirmedCenter.getX() - center.getX()) -
                            Math.abs(firstConfirmedCenter.getY() - center.getY())) / 2);
                    }
                }
            }
            return 0;
        }
    
        /**
         * @return true iff we have found at least 3 finder patterns that have been detected
         *         at least {@link #CENTER_QUORUM} times each, and, the estimated module size of the
         *         candidates is "pretty similar"
         */
        private haveMultiplyConfirmedCenters(): boolean {
            let confirmedCount = 0;
            let totalModuleSize: number /*float*/ = 0.0;
            const max = this.possibleCenters.length;
            for (const pattern of this.possibleCenters) {
                if (pattern.getCount() >= FinderPatternFinder.CENTER_QUORUM) {
                    confirmedCount++;
                    totalModuleSize += pattern.getEstimatedModuleSize();
                }
            }
            if (confirmedCount < 3) {
                return false;
            }
            // OK, we have at least 3 confirmed centers, but, it's possible that one is a "false positive"
            // and that we need to keep looking. We detect this by asking if the estimated module sizes
            // vary too much. We arbitrarily say that when the total deviation from average exceeds
            // 5% of the total module size estimates, it's too much.
            const average: number /*float*/ = totalModuleSize / max;
            let totalDeviation: number /*float*/ = 0.0;
            for (const pattern of this.possibleCenters) {
                totalDeviation += Math.abs(pattern.getEstimatedModuleSize() - average);
            }
            return totalDeviation <= 0.05 * totalModuleSize;
        }
    
        /**
         * @return the 3 best {@link FinderPattern}s from our list of candidates. The "best" are
         *         those that have been detected at least {@link #CENTER_QUORUM} times, and whose module
         *         size differs from the average among those patterns the least
         * @throws NotFoundException if 3 such finder patterns do not exist
         */
        private selectBestPatterns(): Array<Array<FinderPattern>> /*throws NotFoundException */ {
    
            const startSize = this.possibleCenters.length;
            if (startSize < 3) {
                // Couldn't find enough finder patterns
                throw new NotFoundException();
            }
    
            const possibleCenters = this.possibleCenters;
            let average: float;
            // Filter outlier possibilities whose module size is too different
            if (startSize > 3) {
                // But we can only afford to do so if we have at least 4 possibilities to choose from
                let totalModuleSize: float = 0.0;
                let square: float = 0.0;
                for (const center of this.possibleCenters) {
                    const size: float = center.getEstimatedModuleSize();
                    totalModuleSize += size;
                    square += size * size;
                }
                average = totalModuleSize / startSize;
                let stdDev: float = <float>Math.sqrt(square / startSize - average * average);
    
                possibleCenters.sort(
                    /**
                     * <p>Orders by furthest from average</p>
                     */
                    // FurthestFromAverageComparator implements Comparator<FinderPattern>
                    (center1: FinderPattern, center2: FinderPattern) => {
                        const dA: float = Math.abs(center2.getEstimatedModuleSize() - average);
                        const dB: float = Math.abs(center1.getEstimatedModuleSize() - average);
                        return dA < dB ? -1 : dA > dB ? 1 : 0;
                    });
    
                const limit: float = Math.max(0.2 * average, stdDev);
    
                for (let i = 0; i < possibleCenters.length && possibleCenters.length > 3; i++) {
                    const pattern: FinderPattern = possibleCenters[i];
                    if (Math.abs(pattern.getEstimatedModuleSize() - average) > limit) {
                        possibleCenters.splice(i, 1);
                        i--;
                    }
                }
            }
    
            let unusedCenters = new Set(possibleCenters);
            let possibleCodes = [];
            if (possibleCenters.length > 3) {
                // group finders where h1xw1, h1xw2, h2xw1
                // TODO: currently does not account for top1 being a bottomleft corner
                unusedCenters.forEach(top1 => {
                    let bottomLeft: FinderPattern;
                    // remove from set so we dont compare it to itself
                    unusedCenters.delete(top1);
                    unusedCenters.forEach(top2 => {
                        // are at the same height on image (possibe top corners)
                        if(top1.getY() === top2.getY()){
                            // get horizontal distance between the two
                            let Xdistance = top2.getX() - top1.getX();
                            let Ydistance = Xdistance > 0 ? Xdistance + top1.getY() : Math.abs(Xdistance) + top2.getY();
                            unusedCenters.forEach(bottom => {
                                if (bottom.getX() === top1.getX() &&  bottom.getY() === Ydistance && !bottomLeft) { 
                                    // found three corners of a square!
                                    bottomLeft = bottom;
                                    unusedCenters.delete(top2);
                                    unusedCenters.delete(bottom);
                                    // just print for now
                                    console.log(`Corners found! ${top1}, ${top2}, ${bottom}`);
                                    possibleCodes.push([top1, top2, bottomLeft]);
                                    // break; no breaks in forEach or array destructuring in TS
                                }
                            })
                        }
                    })
                })
                console.log(`Grouped codes: ${possibleCodes} 
                            & Unused corners: ${unusedCenters}`);

                // Throw away all but those first size candidate points we found.
                let totalModuleSize: float = 0.0;
                for (const possibleCenter of possibleCenters) {
                    totalModuleSize += possibleCenter.getEstimatedModuleSize();
                }
    
                average = totalModuleSize / possibleCenters.length;
    
                possibleCenters.sort(
                    /**
                     * <p>Orders by {@link FinderPattern#getCount()}, descending.</p>
                     */
                    // CenterComparator implements Comparator<FinderPattern>
                    (center1: FinderPattern, center2: FinderPattern) => {
                        if (center2.getCount() === center1.getCount()) {
                            const dA: float = Math.abs(center2.getEstimatedModuleSize() - average);
                            const dB: float = Math.abs(center1.getEstimatedModuleSize() - average);
                            return dA < dB ? 1 : dA > dB ? -1 : 0;
                        } else {
                            return center2.getCount() - center1.getCount();
                        }
                    });
    
                possibleCenters.splice(3); // this is not realy necessary as we only return first 3 anyway
            }
    
            if (possibleCodes.length > 1) return possibleCodes;

            return [[
                possibleCenters[0],
                possibleCenters[1],
                possibleCenters[2]
            ]];
        }
    }